Navy ships, as well as commercial and other ocean going vessels, rely extensively on steam for powering the vessels as well as for operating auxiliary systems such as the galley, scullery, space heating, laundry, hot water and boiler blanketing. The steam for powering the vessel and for boiler blanketing must be substantially free of carbon dioxide (CO.sub.2) to prevent corrosion. However, most of the other on-board systems do not require this high degree of CO.sub.2 free steam.
In order to achieve a steam substantially free of CO.sub.2, the feed water from which the steam is produced undergoes comprehensive and expensive water treatment processing such as demineralization/reverse osmosis in order to remove bicarbonates. With the bicarbonates removed from the feed water, the export steam produced from the feed water will be substantially free of CO.sub.2 and attain, for example, a near neutral pH of 7 and a conductivity of less than 2 .mu.mho/cm as compared to a pH of near 4 and a conductivity near 10 .mu.mho/cm when CO.sub.2 is present.
When at sea, on-board water purification systems remove bicarbonates from the feed water so that all the steam produced is substantially free of CO.sub.2. However, when ships are in port and berthed at piers, shore boilers produce and provide steam for the ships functions as well as for base facility functions. One of the ship requirements is boiler blanketing (i.e. maintaining steam in the boiler) so that a ship, although berthed, may steam into action without requiring lengthy boiler "fire-up". In this way, Navy ships may maintain battle readiness, necessary to avoid, for example, surprise attack. Unfortunately, boiler blanketing requires steam substantially free of CO.sub.2 but most other on-board ship systems as well as base facilities do not. As a result, present practice is to require the shore boilers to produce a steam substantially free of CO.sub.2 for boiler blanketing. Accordingly, 95% of the steam produced is unnecessarily purified and supplied for other ship functions and base facilities which do not require a high degree of CO.sub.2 free steam.
The present invention, provides a method and apparatus for removing CO.sub.2 and other non-condensible gases from steam and produces a gas-free saturated or superheated steam, eliminating gaseous contaminants with minimal energy loss. With the present invention, only the steam for boiler blanketing (and any other system that may require a high degree of CO.sub.2 free steam) undergoes treatment; the remaining steam systems, on-board and on-shore, supplied with impure steam.